Cardiopulmonary resuscitation (CPR) — whether it’s administered by an emergency medical technician, a hospital emergency room nurse, or a trained colleague in the workplace — can save lives.

But during CPR, what if the person is partially conscious and aware of what’s being done to help them?

Dr. Rune Sarauw Lundsgaard, a Danish anesthesiologist, presented new research into this rare phenomenon earlier this month at the annual European Anesthesiology Congress (EAC) in Copenhagen.

Lundsgaard collaborated with his colleagues in the department of anesthesiology at Copenhagen’s Herlev Hospital and at Nykøbing Falster Hospital.

“Awareness during CPR is an extremely rare event,” Lundsgaard told Healthline, “and was first reported in medical literature in 1989.”

He added that it’s unclear whether the recorded cases have anything in common.

A case history

Lundsgaard studied the 2016 case of a 69-year-old man who had suffered for three days with indigestion and nausea and was admitted to Herlev Hospital in Copenhagen. Lundsgaard was the attending physician.

The patient, shortly after arriving, became unconscious and went into cardiac arrest. Paramedics initiated CPR immediately.

“The cardiac arrest team was in the next room with another patient,” Lundsgaard said. “Advanced CPR was initiated shortly after that. This means that two paramedics and four hospital porters were shifting in pairs of two, performing the CPR.”

“The patient showed no electrical activity in the heart at any time. The heart functioned only because of the manual compressions,” Lundsgaard noted.

In addition to the chest compressions, the team ventilated the patient with a mask that delivered 100 percent oxygen.

By the time the cardiac arrest team arrived, the patient had a blood oxygen level of 100 percent and a high level of awareness, with open eyes and movement of the head and limbs, Lundsgaard says. The six-person team continued to administer advanced CPR for nearly 90 minutes.

“During CPR, the patient responded to verbal communication by moving eyes, lifting hands and legs, and nodding his head,” he said. “The patient’s wife was able to hold his hand.”

The team checked regularly to see if the patient’s heart had begun to beat, but found no rhythm. Following multiple ultrasound echocardiograms during 90 minutes of CPR, Lundsgaard and his colleagues noticed no heart movement.

“From the first moment, according to guidelines, we gave the patient epinephrine (adrenaline) every three to five minutes to attempt to restore his pulse and spontaneous blood circulation,” Lundsgaard said.

The patient was also intubated to clear his airway.

“From the beginning and throughout the treatment, the team performed ultrasonic evaluation,” he added.

The patient showed no sign of aortic dissection until 60 minutes had passed.

Despite the team’s best efforts, the patient didn’t survive.

“An autopsy later confirmed that the patient had suffered a complete aortic dissection,” Lundsgaard said. “This is a serious and often fatal condition in which the inner and outer layers of the aorta separate as blood is forced between them.”

In the research they presented at the EAC in Copenhagen, Lundsgaard and his colleagues summed up their work with the patient.

Their deduction: His high level of awareness, plus oxygen saturation and a level of arterial gas that was almost within the normal range throughout the 90 minutes of CPR, indicated that the patient’s peripheral and cerebral blood flow was good and that their chest compressions had been highly effective.

Although the patient had a poor outlook, the termination of CPR after 90 minutes raised ethical questions for the colleagues, as the patient was still conscious at the time.

Lundsgaard said the patient’s heart never exhibited any spontaneous rhythm and didn’t appear to move during multiple ultrasound evaluations. Consequently, a surgical intervention wasn’t recommended.

“We consulted several thoracic surgeons at different hospitals, and they all agreed that the prognosis for an operation was very poor,” he said. “Although awareness during CPR is rare, it raises the question of proper sedation during resuscitation, which is not currently part of the guidelines.”

Can you be conscious?

Are there different degrees of awareness during CPR?

“Little is still known about this,” Lundsgaard said. “The case reports up until now have different degrees of awareness. Some have spontaneous breathing or responsiveness to pain, others full awareness with open eyes and verbal response. Doctors have yet to agree on a standardized way of reporting or describing degrees of awareness during CPR.”

Another leading researcher in this field is Dr. Sam Parnia, director of critical care and resuscitation research at New York University’s Langone Health.

He’s also the principal author of a landmark 2014 study, “AWARE – AWAreness during REsuscitation,” conducted while he led a multidisciplinary team of medical scientists at Southampton University in England.

Referring to the Lundsgaard research presented at the EAC, Parnia told Healthline, “It is exceedingly rare for people to have actual awareness with external signs of being conscious.”

“All the studies of CPR have demonstrated that there is insufficient blood flow to the brain (approximately 15 percent of baseline blood flow) to allow for the return of brain stem reflexes and consciousness with external signs of being awake,” he explained.

“It is much more likely to have people waking up during compressions when the additive effect of compressions on an already beating heart raises the blood pressure to a sufficient level to provide enough blood flow to the brain,” he added.

Personal remembrances

Parnia’s 2014 study looked at 2,060 patients with cardiac arrest — 330 of them survived, and 140 said they had been partly aware at the time of resuscitation.

Parnia said that of those 140 who reported being partly aware, slightly more than 50 “described a perception of awareness but did not have any explicit memory of events.”

He said that response suggests that “more people may have mental activity initially but then lose their memories, either due to the effects of brain injury or sedative drugs on memory recall.”

Parnia said one in five patients said they had felt an “unusual sense of peacefulness, while nearly one-third said time had slowed down or speeded up. Some recalled seeing a bright light, a golden flash, or the sun shining.”

“Others recounted feelings of fear or drowning or being dragged through deep water,” he added. “Thirteen percent said they had felt separated from their bodies, and the same number said their senses had been heightened.”

Surprising findings

Parnia’s study was published in Resuscitation, the journal of the European Resuscitation Council. Among his discoveries:

  • In some cases of cardiac arrest, memories of visual awareness compatible with so-called out-of-body experiences may correspond with actual events.
  • A higher proportion of people may have vivid death experiences but don’t recall them because of brain injury or sedative drugs on memory circuits.
  • Widely used yet scientifically imprecise terms such as near-death and out-of-body experiences may not be sufficient to describe the actual experience of death. Future studies should focus on cardiac arrest, which is biologically synonymous with death, rather than ill-defined medical states sometimes referred to as “near-death.”
  • The recalled experience surrounding death merits a genuine investigation without prejudice.

“Contrary to perception, death is not a specific moment but a potentially reversible process that occurs after any severe illness or accident causes the heart, lungs, and brain to cease functioning,” Parnia said.

“If attempts are made to reverse this process, it is referred to as ‘cardiac arrest.’ However, if these attempts do not succeed, it is called ‘death.’ In this study, we wanted to go beyond the emotionally charged yet poorly defined term of near-death experience to explore objectively what happens when we die,” he explained.

Difficult moments for the CPR team

“The cardiac arrest team in our case was very affected by the situation,” Lundsgaard said. “For me, having to tell the patient that we were unable to save his life — and that in a minute we will stop chest compressions and you will not survive — was a challenging situation.”

The experience also raised some difficult ethical questions for the medical personnel, including the issue of sedating patients during resuscitation, he said.

“The question of sedation during CPR is not new, but sedation is not routinely performed during CPR,” Lundsgaard said. “This is an area that needs further research.”

For those who survive such incidents, the long-term effects on mental well-being are unknown.

“We know from anesthesia that accidental awareness during operations often lead to post-traumatic distress and decreased quality of life,” Lundsgaard said. “One might suspect that awareness during CPR may be just as stressful.”

Lundsgaard’s next research aims to unpack ethical questions.

“I believe that further attention and research should be directed to the area of sedation during CPR,” he said. “At this time, we in the medical profession are not attending to the pain we cause, nor are we aware about patients’ levels of consciousness during CPR. This should be an area of future research.”